Spray Deposited Ni Doped ZnO Nanoparticles for Ammonia Vapour Sensing

ZnO is one of the most important semiconductor materials having a variety of applications in photonic, field emission and sensing devices. Ni doped ZnO films were deposited on glass substrate by spray pyrolysis technique. X-ray diffraction result indicates polycrystalline nature of the films with hexagonal wurtzite structure. The SEM and AFM micrographs indicate the presence of nanocrystallites with agglomeration present over the film surface. The grain size is found to be 15-95 nm. The prepared ZnO doped films exhibit direct band gap.. The vapour sensing characteristics of the Ni (0.0002M) doped ZnO (0.1) film were studied by chemiresistive method for various concentrations of ammonia vapour at room temperature (~ 30 °C). The gas sensing studies indicate that as concentration of ammonia increases the sensitivity increases. For 80 ppm of ammonia vapour, the film shows a response and recovery time of 12 and 21 s respectively.